Transcriptome sequencing, annotation and expression analysis of Nannochloropsis sp. at different growth phases.

Nannochloropsis sp. is an oil-rich microalga. The lipid content of cells at stationary growth phase was much higher than that of cells at logarithm growth phase, but very little information focusing on the abundances of gene transcripts concerning lipid accumulation is available. In present study, the second generation Illumina sequencing was used to investigate the genes and pathways of Nannochloropsis sp. in order to identify those involved in lipid metabolism. In total, 29,203 unigenes were obtained from logarithm and stationary growth phases. The transcripts of some unigenes were differentially abundant at two growth phases. Among the unigenes obtained, about 195 unigenes were involved in lipid metabolism and 315 unigenes were putatively transcription factors. These genes are a very useful resource for the future studies of Nannochloropsis sp.